An al-Qaeda offshoot is encouraging revolt in Yemen. The key U.S. ally faces new threats from two leading tribal groups, who join protesters one day after at least five people – and perhaps 11 – were killed in clashes on Friday.

Amnesty International stated that 11 people died, bringing the total death toll to 27 since anti-government demonstrations began to demand the resignation of President Ali Abdullah Saleh, whose soldiers reportedly opened gunfire on protesters Friday night.

The Arabian Peninsula al-Qaeda group, an offshoot of the Yemen-based terrorist network, produced and posted an audio tape on Saturday, urging revolutions. The speaker was Ibrahim al-Rubeish, a former detainee at the Guantanamo Bay prisoner facility run by the United States, according to the SITE Intel organization, which monitors terrorist websites.

The tape was produced by al-Qaida in the Arabian Peninsula, a Yemen-based offshoot of the terror network, reports the SITE Intel group, a U.S.-based group that monitors extremist websites.

"One tyrant goes, only to be replaced another who may fix for the people some of their worldly issues by offering job opportunities and increasing their income, but the greater problem remains," al-Rubeish said.

The Yemen Solidarity Council, most of which is comprised of Saleh’s own Hashid tribe, demanded an end to the bloodshed. "The Yemeni people will not stay quiet on the blood that was spilled in Aden and we will avenge it for them," said Hussein Ahmar, president of the Council, whose withdrawal of support for Saleh has placed the ruler’s regime in jeopardy.

"We call on all those loyal to Yemen to stand with the revolution until this regime falls,” he said.

Contributing to the threat to Saleh are high unemployment and a water shortage, circumstances that al-Qaeda is exploiting in its call for a Shi’ite revolution.

Yemen is a base for al-Qaeda’s attempts to attack the United States, and the Obama administration fears the fall of Saleh could set off full-fledged anarchy and terror in more areas in the Middle East.

The kingdom of Morocco also faced large-scale protests on Sunday, which were expected to be peaceful. Five people died in demonstrations last Sunday.

"King Mohammed is well aware of" and "taking appropriate action" to meet the aspirations of Moroccans, U.S. State Department spokesman Philip J. Crowley told reporters last week.

Several Moroccan websites have reported that the king will replace his prime minister and cabinet.

In Bahrain, another key American ally, senior Shi’ite opposition leader Hassan Mushaima has returned from exile and will likely strengthen protests against the regime.

Protests also continue in Algeria, where President Abdelaziz Bouteflika has deployed a large police force.

In Tunisia, the interim government has temporarily banned all traffic, including that of pedestrians, on the capital’s main street after rock-throwing protesters clashed with police and soldiers, some of whom manned tanks. The opposition has accused the interim government of hijacking the revolution.